The above-described method sometimes referred to as a replica process, is notably suitable for the manufacture of high quality optical components such as lenses and mirrors. It concerns components having a complicated refractive surface, for example, an aspheric surface.
The matrix used in the method is usually manufactured from quartz as is described, for example, in Netherlands Patent Application No. 8301482 and the corresponding U.S. Pat. No. 4,534,929; Netherlands Patent Application No. 8400868 and the corresponding U.S. Ser. No. 618,799 filed Jun. 8, 1984 now U.S. Pat. No. 4,756,972; and British Patent Specification 1,301,551.
The curable monomer composition used in the method may be a thermal hardening resin as is mentioned in the above-mentioned British Patent Specification. A light-curable, for example UV light-curable, monomer composition is preferably used, for example, a mixture of acrylates and a photoinitiator. Such a monomer composition is mentioned in the above Netherlands Patent Applications both in the name of the inventions of the present invention.
A matrix of glass or quartz presents the advantage of a good non-deformability, great hardness and a very strong resistance to chemical attack, such as for example, oxidation. An advantage which is very important for practical purposes is that the monomer composition is exposed via the transparent matrix and can be cross-linked (cured). The use of a stainless steel matrix as described in the U.S. Pat. No. 4,432,832 does not have this important advantage. Moreover, a stainless steel matrix is by far less resistant to chemical attack.
A disadvantage of the use of a matrix of glass or quartz is that it has not proved possible to grind the glass or quartz surface to the desired accuracy in a reproducible manner. All the matrices used in a mass production process mutually have slightly different refractive surfaces. This means that the components manufactured by means of such matrices do not have a uniform reproducible quality.
It is the object of the invention to provide a method in which the manufactured components have the same uniform reproducible quality. Another object is to use in the method matrices which can be produced in large numbers, rapidly, cheaply and especially with great uniform accuracy.